Microcrystalline cellulose, also known and referred to herein as “MCC,” hydrolyzed cellulose wet cake, or cellulose gel, is commonly used in the food industry to enhance the properties or attributes of a final food product. For example, it has been used as a binder and stabilizer in food applications, including in beverages, as a gelling agent, a thickener, a fat substitute, and/or non-caloric filler, and as a suspension stabilizer and/or texturizer. It has also been used as a binder and disintegrant in pharmaceutical tablets, as a suspending agent in liquid pharmaceutical formulations, and as a binder, disintegrant, and processing aid in industrial applications, in household products such as detergent and/or bleach tablets, in agricultural formulations, and in personal care products such as dentifrices and cosmetics.
Microcrystalline cellulose is modified for such uses by subjecting micro-crystalline cellulose or “wet cake” to attriting processes to substantially subdivide the crystallites into finely divided particles. However, as particle size is reduced, the individual particles tend to agglomerate or hornify upon drying, a result that is undesirable in product manufacture or use. To prevent hornification, a protective colloid may be added during attrition or following attrition but before drying. The protective colloid wholly or partially neutralizes the hydrogen or other bonding forces between the smaller sized particles. The resulting materials are frequently referred to as attrited microcrystalline cellulose or colloidal microcrystalline cellulose and such attrited or colloidal microcrystalline cellulose will typically form stable suspensions with little to no settling. In contrast, non-colloidal microcrystalline cellulose will settle and not form a stable suspension in aqueous systems. Colloidal microcrystalline cellulose, such as carboxymethyl cellulose-coated microcrystalline cellulose, is described in U.S. pat. No. 3,539,365 (Durand, et al). Another colloidal microcrystalline cellulose, such as starch-coated microcrystalline cellulose, is described in US Pat. App. 2011/0151097 (Tuason et al.). FMC Corporation (Philadelphia, Pa., USA) manufactures and sells various colloidal microcrystalline cellulose products, including edible food and pharmaceutical grades, under the names of, among others, AVICEL® and GELSTAR®.
Admixtures of MCC and some hydrocolloids (such as carboxymethyl cellulose having a degree of substitution of at least 0.95, pectin, alginate, carrageenan, xanthan gum, agar gum, wellan gum, or gellan gum) may be too ‘slippery’ to be satisfactorily attrited. Less than satisfactory attrition of the MCC particles can have a deleterious effect on the functionality of the MCC stabilizer. As a result, some attempts have been made to solve this problem by using an attriting agent, for instance, a salt. For example, see U.S. Pat. Nos. 7,879,382, 7,462,232 and 5,366,724. Other approaches have been taken to make suitable MCC/hydrocolloid compositions. For example, see US 2005/0233046; US 2011/0151097; and WO 2010/136157.
There remains a need, however, for a co-attrited colloidal microcrystalline cellulose composition containing a carboxymethyl cellulose having a degree of substitution of at least 0.95 (such carboxymethyl celluloses being slippery). Applicants have unexpectedly found that using a carboxymethyl cellulose having a degree of substitution of from 0.95-1.5 and a viscosity of less than 100 cps is capable of being co-attrited with MCC and that such co-attrited stabilizer compositions provide superior stabilization in, for example, aqueous food systems.